After Canon instance rebate, the lens is $598 with $9.95 shipping.
With bing cash back via paypal (instance credit back to your paypal account), it will bring the price down to $478.4 + $9.95 shipping.

The EF 85mm f/1.8 lens from them is around $303 + shipping after cash back.

Last time I bought my EF 85mm lens from Beach Camera via ebay, I was able to get it less than $300 before shipping (brand new). The used market for that lens cost about the same at that time. And I got the cash back right after I complete the transaction.

Does this top out at $200 back? I think that is what it was last year for Live.com. Either way, last year I got 25% on eBay with PayPal offering 10% on top. Smoking deal.

BTW, is this instant this year? Last year it was 6 weeks I think.
EDIT:

You can request your cashback about 60 days after your purchase (the waiting period varies by store)

You may earn up to Two Thousand Five Hundred U.S. Dollars ($2,500.00) of cashback savings in a calendar year, calculated based on when the participating store reports your purchases to us. You may earn cashback savings on purchases that you complete in the same web browsing session (not to exceed 24 hours) after clicking on advertisements or listings in the Bing service or the Bing cashback service. Eligible advertisements will be marked with the Bing cashback logo.

I am not seeing anything that says you cannot get up to $2500 in a single purchase. But then, I only skimmed it. But I don't think you will get it right away either, it will be over a month you have to be willing to front the money...which isn't terrible given the end savings.

Quick cashback is a way to get your cashback immediately and avoid waiting the normal 60-day pending period. If you make a qualifying purchase from an eligible merchant, your cashback will be rewarded soon after purchase. To be eligible for quick cashback, you must meet these three criteria:

You've joined the quick cashback program. (You can do this from your cashback account.)

You've kept your PayPal account in good standing.

You make a qualifying purchase from an eligible store and complete the purchase using PayPal.

You're eligible to receive quick cashback when you meet these criteria, but it doesn't guarantee that you'll receive a quick cashback reward. Any eligible purchase that doesn't meet all of the criteria for quick cashback but meets all of the other cashback requirements will wait for possible returns in the normal 60-day pending period.

As with any cashback purchase, your purchase must meet all of the requirements of the Microsoft Service Agreement to be eligible for cashback savings.

Here are a few more details about quick cashback:

We'll deposit quick cashback rewards in the PayPal account that you used during your purchase.

We'll email you if your cashback is rewarded with quick cashback.

The rules that apply to returning or canceling a purchase also apply to quick cashback rewards.

When I bought my 85mm lens 1/2 year ago, They credit my my paypal account instantly. But of course, at that time, Beach camera lower their price on the lens and the cash back was only 10%-12% (something like that).

Now that I am ready to buy, this doesn't seem to be working very well. Last year was flawless. This year a google search reveals different % for different searches, but right now as of this typing it seems to be 8% across the board for eBay, not 20%.

Now save that ebay link, clear your cookies from your browser and revisit it to double check that price is in fact as they claim.

Some companies were recently sprung artifically inflating the price for customers who came to the site with bing cookies in their web browser. In that case they offered a small discount on a very much higher priced product, and it was actually cheaper not to use bing cash back.

It will change rapidly during the holiday season. Ita back to 8% for now. Keep an eye out at slickdeals.net or other deal sites and they will announce when it rises. It was at 15% for a few days and 20% for maybe a day or 1.5 days. That's a great deal if you can catch it.